Biomedical subjects

L Kangas

Publications and source records attributed to L Kangas.

At least 37 records · Page 2Linked to original sources

PubMed1996

Expression of laminin in renal-cell carcinomas, renal-cell carcinoma cell lines and xenografts in nude mice.

We studied the expression of laminin (Ln) chains (alpha1-alpha3, beta1-beta3, gamma1) in human renal-cell carcinomas (RCC), papillary renal neoplasms (PRN) and oncocytomas, in RCC cell lines and their xenografts. In RCCs the basement membranes (BM) showed immunoreactivity for chains of Ln-1 (alpha1-beta1-gamma1). Only in well-differentiated RCCs could vessel BMs be distinguished from those of carcinoma cell islets. RCCs and oncocytomas also exhibited an abundant immunoreactivity for Ln beta2 chain in both vessel and tumor cell BMs, while Ln alpha2 chain was not seen in any renal tumors. In distinction from RCCs, PRNs presented a strong BM immunoreactivity for Ln alpha3 and beta3 chains and for Ln-5, as well as lack of Ln beta2 chain. A more variable reactivity for Ln-5 was seen in oncocytomas. As PRNs and oncocytomas have been suggested to originate from collecting ducts, it is notable that in normal human kidney, we could detect immunoreactivity for Ln-5 and its chains only in BM of the tubules of the loop of Henle. In immunoprecipitation experiments, an abundant production of Ln-1, but not of Ln-5, was seen in cultured RCC cells, while in xenografts of the same cells BM-confined immunoreactivity for both Ln-1 and Ln-5 was seen. Ln beta2 chain was produced by 2 of the 4 RCC cell lines in culture but was found only in 1 of the xenografted tumors.

Adenoma, Oxyphilic↗

PubMed1996

Anti-estrogens enhance the therapeutic effect of lymphokine-activated killer cells on the P815 murine mastocytoma.

Tamoxifen (TX) and toremifene (TO) enhanced the lysis of P815 mastocytoma cells in vitro by syngeneic DBA2 spleen cells that have been activated by human recombinant interleukin-2 (IL-2) for 6 days (lymphokine-activated killer [LAK] cells). Similarly, enhanced tumor suppression occurred when TX- or TO-treated P815 cells were mixed with LAK cells and injected s.c. into normal DBA2 recipients. Tumor suppression could be increased further by treating such recipients orally with TX or TO and by the repeated injections of LAK cells into the tumor site. The treatment of animals bearing tumors (5 mm in diameter) orally with TX or TO or with LAK cells i.p. resulted in tumor suppression. When the drug treatment was combined with LAK cells, tumor suppression was more pronounced, and complete tumor regression was induced in a significant number of the animals so treated. Our results indicate that the immunotherapeutic effect of LAK cells can be significantly amplified by combined treatment with the anti-estrogens TX or TO.

Analysis of Variance↗

PubMed1996

Genotoxicity of dihydroabikoviromycin, a secondary metabolite of Streptomyces anulatus.

The potential genotoxicity of dihydroabikoviromycin was assessed in bacterial and sister-chromatid exchange (SCE) test systems. Direct cytotoxicity was also assayed using bioluminescence methods to screen for differences in cell viability among different tumour cell lines following exposure to the drug. Differential killing tests with Escherichia coli WP2 and its repair-deficient derivative CM871 indicated that a functional DNA repair system was protective against the action of dihydroabikoviromycin, implying that this compound causes some form of DNA damage and is almost certainly therefore genotoxic. Dose-dependent reversion from His- to His+ with dihydroabikoviromycin was observed in the Ames test with Salmonella typhimurium TA100, but not in frameshift tester strain TA98. Dihydroabikoviromycin also induced the sfiA gene, as indicated by beta-galactosidase induction in an SOS-chromotest with E. coli PQ37 strain. A dose-related increase in SCEs by dihydroabikoviromycin was observed in CHO cells. Growth of tumour cells was also suppressed by dihydroabikoviromycin at a dose of 10 micrograms/ml.

Animals↗

PubMed1996

Chemosensitivity of human melanoma metastases in mouse subrenal capsule assay--can it predict tumour response to combined cytostatic plus interferon therapy in metastatic melanoma?

We have analysed the chemosensitivity of 121 human melanoma metastases in the 6-day mouse subrenal capsule assay (SRCA). A total of 13 different chemotherapy regimens were analysed in four successive series. By the original criteria of the assay, 75% of tumours were sensitive to at least one regimen. The most effective combinations, giving sensitivity rates > 40%, were of dacarbazine, vincristine, and BCNU (DOB) with or without metronidazole, followed by cisplatin plus etoposide (Plat-VP16) combined with interferon. On the basis of the SRCA screening we developed a four-drug chemotherapy regimen combined with interferon for metastatic melanoma. Retrospectively analysed the assay correctly identified 77% of clinical responders and 54% of clinical non-responders. The overall predictive accuracy was 65%. Despite the limitations of the assay, it can be used for screening new drugs or combinations.

Animals↗

PubMed1996

A two-year dietary carcinogenicity study of the antiestrogen toremifene in Sprague-Dawley rats.

The carcinogenic potential of the nonsteroidal triphenylethylene antiestrogen toremifene (Fareston) was evaluated in a standard 104-week rat dietary carcinogenicity study. The doses were 0, 0.12, 1.2, 5.0 and 12 mg/kg/day and the number of animals 50/sex/dose group. The body weight gain and food consumption were monitored once weekly (study weeks 1-16) or once every four weeks thereafter (study weeks 17-104). Blood samples were taken at weeks 34, 52 and 104 and the plasma concentrations of toremifene, as well as the two main metabolites (deaminohydroxy)toremifene and N-demethyltoremifene, were measured. All doses of toremifene reduced food intake and body weight gain. Toremifene caused a significant reduction in mortality, which was mainly due to reduced incidences of pituitary tumors. This was evident in all dose groups. Drug-related decrease of mammary tumors in females (at all doses) and testicular tumors in male rats (doses > or = 1.2 mg/kg/day) were also evident. The incidence of the preneoplastic foci of basophilic hepatocytes were significantly decreased in treated female groups. Toremifene induced no preneoplastic or neoplastic lesions. Based on histopathology, no obvious toxicity could be observed. Drug-related changes were observed in the genital organs, thyroid, spleen, mammary gland, adrenal, kidney, stomach and lung. These changes were due to hormonal disturbances or as a result of reduced food consumption or reduced incidences of pituitary, mammary or testicular tumors. This study indicates that toremifene is an efficient antiestrogen in long-term treatment, is well tolerated and has no tumorigenic potential in rats.

Aging↗

PubMed1995

Expression of E- and N-cadherin in renal cell carcinomas, in renal cell carcinoma cell lines in vitro and in their xenografts.

E- and N-cadherins are proteins involved in intercellular adhesion and are localized, e.g., in the adherens junctions of epithelial cells. Kidney tubules express these molecules in a distinctive pattern, the expression of N-cadherin being restricted to proximal tubules and that of E-cadherin to distal tubules and collecting ducts. Renal cell carcinomas (RCCs) and oncocytomas are considered to originate from these tubular epithelia. To find out whether cadherins could serve as markers for a cellular origin of these tumors, we studied the expression of E- and N-cadherins in RCCs and oncocytomas, in cell lines derived from RCCs as well as in tumors grown in nude mice. Most RCCs co-expressed E- and N-cadherins, as did 2 of the 4 cell lines studied. The expression pattern did not correlate with the histological grade of the tumors, and even the least differentiated tumors, as well as metastases, showed expression of cadherins. Renal oncocytomas expressed E-cadherin but not N-cadherin, which is in line with previous studies that have proposed a collecting duct origin for these tumors. Papillary renal neoplasms, a separate entity usually not classified as RCC, expressed neither of the cadherins studied despite the abundant expression of beta-catenin. Our results suggest that most RCCs co-express the characteristic adhesion molecules of both proximal and distal tubules, which makes it questionable whether the origin of these tumors can be reliably located to any distinct part of the renal tubule. Our results also suggest that in RCCs the increased histological grade is not directly associated with changes in the expression of either of the cadherins, indicating other mechanisms underlying the deficient capacity to form polarized tubular structures.

Aged↗

PubMed1995

Tenascin and fibronectin isoforms in human renal cell carcinomas, renal cell carcinoma cell lines and xenografts in nude mice.

We studied the expression of tenascin (Tn) and isoforms of fibronectin (Fn) in human renal cell carcinomas (RCC) and oncocytomas, in RCC cell lines and in their s.c. implanted xenografts in nude mice. In well-differentiated RCCs and oncocytomas extra-domain A (EDA)-Fn and Tn immunoreactivities were confined to the basement membranes and blood vessels, while in less-differentiated RCCs they were also widely seen in the stroma, correlating with the morphological differentiation of the tumor. Expression of EDB-Fn and oncofetal (onc)-Fn was very scarce in most of the RCCs and oncocytomas. Western blotting results demonstrated the predominance of the M(r) 190,000 Tn subunit in most RCCs. Among the 4 RCC cell lines, 3 showed Tn in the extracellular matrix. As xenografts, they formed moderately or poorly differentiated tumors, with abundant Tn. Three of the RCC cell lines also showed secretion of EDA-Fn and 2 of them secretion of onc-Fn and EDB-Fn into the culture medium, while in xenografts there was a strong expression of all Fn isoforms. In xenografts, the expression of Tn closely recapitulated that seen in clinical tumors and in the cell lines in vitro, while the expression of Fn isoforms in cultured cells and their xenografts was highly discordant.

Animals↗

PubMed1995

Pharmacokinetics and metabolism of 2-[18F]fluoro-2-deoxy-D-glucose (FDG) in mammary tumors of antiestrogen-treated rats.

Attempts are being made to evaluate 2-[18F]fluoro-2-deoxy-D-glucose (FDG) as a noninvasive marker of therapy response in malignant tumors. We studied rats with 7,12-dimethylbenzanthracene (DMBA)-induced mammary carcinomas by measuring the differential absorption ratio (DAR) and the metabolites of FDG in tumor homogenates. Half the rats were treated with the antiestrogen toremifene for 14 days and half were untreated. The histology of the tumors was studied by morphometry. The animals were killed 15, 45 or 240 min after injection. Regardless of whether the rats received toremifene or not, the fractional change in tumor volume correlated better with the DAR at 15 min [r = 0.284 (untreated) and r = 0.721 (treated)] and at 240 min [r = 0.932 (untreated)], than at 45 min [r = -0.137 (untreated) and r = 0.265 (treated)]. Inverse relations were found for the fraction of unmetabolized FDG and change in tumor volume [r = 0.070 (45 min) and r = -0.872 (240 min) for untreated tumors and r = -0.963 (15 min) and r = -0.715 (45 min) for treated tumors]. The DAR and the fraction of unmetabolized FDG correlated also [r = -0.420 (15 min), r = -0.647 (45 min) and r = -0.976 (240 min) for untreated tumors, and r = -0.963 (15 min) and r = -0.213 (45 min) for treated tumors]. No significant therapy-induced morphometrical changes were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1995

Tamoxifen and toremifene lower serum cholesterol by inhibition of delta 8-cholesterol conversion to lathosterol in women with breast cancer.

PURPOSE: Long-term effects of tamoxifen and toremifene, a new antiestrogen that closely resembles tamoxifen, were investigated on serum lipids and cholesterol metabolism. PATIENTS AND METHODS: The study group consisted of 24 postmenopausal Finnish women with advanced breast cancer from an international multicenter study of 415 patients. Cholesterol metabolism was evaluated by measuring the cholesterol precursor (delta 8-cholestenol, desmosterol, and lathosterol, reflecting cholesterol synthesis) and plant sterol (markers of cholesterol absorption) and cholestanol levels by gas-liquid chromatography. RESULTS: Tamoxifen and toremifene lowered significantly serum low-density lipoprotein (LDL) cholesterol levels after 12 months of treatment by 16% and 15%, with no change in high-density lipoprotein (HDL) cholesterol or serum triglyceride levels. Serum delta 8-cholestenol was increased 40- and 55-fold during toremifene and tamoxifen treatment, respectively, while the increase of desmosterol less than doubled and was lacking for lathosterol by toremifene. Plant sterols and cholestanol were only inconsistently increased in serum. CONCLUSION: Tamoxifen and toremifene inhibit the conversion of delta 8-cholestenol to lathosterol so that serum total and LDL cholesterol levels are lowered by downregulation of cholesterol synthesis. Thus, inhibition of the delta 8-isomerase may be the major hypolipidemic effect of these agents. Reduced risk of coronary artery disease will probably occur also during long-term toremifene treatment, because the drug reduces cholesterol and its synthesis, similarly to tamoxifen.

Antineoplastic Agents, Hormonal↗

PubMed1994

Integrins and laminins in human renal carcinoma cells and tumors grown in nude mice.

We studied by indirect immunofluorescence microscopy the distribution of integrins and laminins in four human renal cell carcinoma cell lines (CAKI-2, A498, CAKI-1, and ACHN) in vitro and in s.c. xenografts in nude mice. In vitro, all four cell lines expressed the alpha 1, alpha 3, alpha v, beta 1, beta 3, and beta 5 subunits and three expressed the alpha 6 subunit; all cell lines expressed laminin A, B1, and B2 chains. Histologically, the CAKI-2 and A498 cells formed differentiated grade 1 (G1) and G2 tumors, respectively, while the CAKI-1 and ACHN cells formed poorly differentiated G3 tumors. The described integrin profile was largely retained upon xenografting. Basal polarization of the alpha 3 and alpha 6 integrin subunits was found in the differentiated tumors, and human laminins were detected as discrete linear structures surrounding tumor cell clusters in these tumors, suggesting that the cells have retained a polarized cell-laminin interaction characteristic of normal tubular epithelial cells. A disorganized distribution of integrins and laminins was noted in the G3 tumors. We conclude that these renal carcinoma cell lines displayed an integrin repertoire similar to that of clinical renal carcinomas and retained it upon xenografting. Furthermore, the organization of integrins and laminins in the xenografts correlated with histological grade.

Animals↗

PubMed1994

Involvement of cytochrome P450 3A enzyme family in the major metabolic pathways of toremifene in human liver microsomes.

The anti-estrogen toremifen-Fc-1157a or 4-chloro-1,2-diphenyl-1-[4-[2(N,N-dimethylamino)ethoxy]-phenyl]-1- butene is now used for the treatment of breast cancer. This drug is extensively metabolized by cytochrome P450 dependent hepatic mixed function oxidase in man, yielding mainly the N-demethyl-(DMTOR), 4-hydroxy-(4OH-TOR) and deamino-hydroxy-(TOR III) toremifene metabolites. The specific forms of cytochrome P450 involved in these oxidation reactions were examined in 32 human liver microsomal preparations previously characterized with respect to their contents of several known P450 enzymes. Toremifene was demethylated with an apparent Km of 124 microM while it was hydroxylated with an apparent Km of 139 microM. The metabolic rates were 71 +/- 56, 13 +/- 9 and 15 +/- 4 pmol/min/mg microsomal protein, respectively, for DMTOR, 4-OH-TOR and TOR III. The N-demethylation activity was strongly correlated with estradiol 2-hydroxylation (r = 0.75), nifedipine oxidation (r = 0.86), tamoxifen N-demethylation (r = 0.73), testosterone 6 beta-hydroxylation (r = 0.78) and erythromycin N-demethylation (r = 0.84), all these monooxygenase activities known to be supported by CYP3A4 isoform. Furthermore, the CYP3A content of liver microsomal samples, measured by western blot analysis using a monoclonal anti-human CYP3A4 antibody, was strongly correlated with DMTOR formation (r = 0.80). Compounds such as cyclosporin, triacetyl-oleandomycin and testosterone inhibited the N-demethylation of toremifene metabolism at 80, 89 and 56% vs control, respectively, while the formation of TOR III was inhibited at 78, 82 and 73% vs control and the 4-hydroxylation pathway was inhibited no more than about 50% vs control. Prior incubation of microsomes with 100 microM gestodene, known to be a selective mechanism-based inhibitor of CYP3A4 in the presence of NADPH, led to 76 +/- 6 and 76 +/- 5% (N = 5 samples) reductions in the N-demethylation and formation of TOR III, respectively. Polyclonal antibody directed against human CYP3A enzymes inhibited formation of DMTOR and TOR III by 60 and 46%, respectively. The metabolism of toremifene was not activated by alpha-naphthoflavone. Finally, the use of yeasts genetically engineered for expression of human P4501A1, 1A2, 2C9 and 3A4 allowed us to demonstrate that DMTOR and TOR III formations are mediated by P4501A and 3A4 enzymes and by contrast these enzymes are not involved in the 4-hydroxylation pathway.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1994

Influence of toremifene on the endocrine regulation in breast cancer patients.

In a combined phase I-II study, the hormonal effects of toremifene (TOR) were investigated in 30 patients. Half of the patients received continuous therapy of TOR 60 mg and half 300 mg of TOR orally daily. Serum concentrations of oestradiol (E2), progesterone (PROG), testosterone (TE), follicle stimulating hormone (FSH), luteinising hormone (LH), prolactin (PRL), human growth hormone (hGH) and sex hormone binding globulin (SHBG) were monitored prior to the treatment and at the second, sixth, eighth and twelfth weeks. The influence of TOR upon the hypothalamo-hypophyseal axis was investigated by the TRH (thyroid-stimulating hormone releasing hormone) functional test using 400 micrograms intravenous injection of TRH for stimulation of PRL secretion. The concentration of E2 decreased during the TOR therapy with 60 mg and 300 mg causing 82 and 71% decreases, respectively (non-significant). PRL was significantly (P < 0.001) suppressed. Both these effects reflect the anti-oestrogenic action of TOR. SHBG increased significantly at both doses of TOR, probably due to a direct oestrogen-like effect of TOR in the liver. TE decreased as a consequence of the elevated SHBG. The TRH-induced PRL release was suppressed by both doses of TOR. There were 17 and 27% reductions at 12 weeks in the 60 and 300 mg groups, respectively. Other hormones measured were not significantly affected by TOR. The hormonal effects of 60 and 300 mg doses of TOR did not differ significantly. Anti-oestrogenic (i.e. decrease of E2), and partially oestrogenic (i.e. increase of SHBG) properties as well as the antiprolactinic effects of TOR may have an overall beneficial effect in the clinical management of breast cancer patients.

Adult↗

PubMed1994

Mouse subrenal capsule assay chemosensitivity and DNA flow cytometry parameters of human melanoma metastases.

Chemosensitivity was analyzed by mouse subrenal capsule assay (SRCA) in 103 human melanoma metastases 79 of which were also analyzed by DNA flow cytometry. The most effective combination was dacarbazine, vincristine, and carmustine (DOB), followed by cisplatin plus etoposide (Plat-VP16). By the original criteria of the assay, 35% of tumors were sensitive to DOB treatment while 15% responded to Plat-VP16. Chemosensitivity of DNA diploid and aneuploid tumors showed no significant difference; 35% of the aneuploid tumors were sensitive to DOB and 19% to Plat-VP16, whereas 41% and 13% respectively of the diploid tumors were sensitive. An association between DNA index and chemosensitivity was observed. Growth of the implant was observed in 44% of tumors with a DNA index above 1.5 receiving DOB treatment, whereas only 12% of tumors with an aneuploid DNA index < or = 1.5 grew. No significant difference was observed in the SPF of chemotherapy sensitive and insensitive tumors, though a tendency to lower SPF was observed in sensitive tumors.

Adult↗

PubMed1993

Effect of Toremifene in patients with metastatic melanoma: a phase II study of the EORTC Melanoma Cooperative Group.

The EORTC Melanoma Cooperative Group conducted a phase II trial (study number 18891) to study the effect of Toremifene in 45 patients with advanced, metastatic melanoma. Male and female patients, median age 61 (range 23-88) years received a mean total dose of 11 g (4.3-62.6) orally for at least 6 weeks. No objective remissions were seen. Four patients (3 women and 1 man; 9%) experienced 3-6 months' disease stabilization. The toxicity of the drug, given at a dose of 240 mg daily, was negligible. Because of the minimal side-effects, Toremifene may be recommended for patients who have only a small number of slowly growing metastases, in particular to soft tissue and lung.

Adult↗

PubMed1992

Chemosensitizing effect of an antiestrogen, toremifene, on ovarian cancer.

The chemosensitizing effect of an antiestrogen, toremifene, was studied on 2 human ovarian cancer cell lines in vitro and on 3 fresh surgical ovarian tumor explants with the aid of the subrenal capsule assay (SRCA). Also, 11 patients with secondarily drug resistant, recurrent gynecologic cancer (8 ovarian and 3 uterine cancers) were treated with 240 mg toremifene daily for 1 week before each course of cytostatics. Toremifene potentiated the effect of doxorubicin on both cell lines. This was also the case on 1 cell line that was not completely resistant to doxorubicin. The SRCA showed a clear potentiating effect of toremifene only on the tumor overtly resistant to the combination of cisplatin, doxorubicin, and cyclophosphamide. Of the 11 patients treated with toremifene and cytostatics, the response of 8 patients was evaluable: 3 had partial response, 3 no change, and 2 progressive disease. Toremifene seems to have a chemopotentiating effect on gynecologic drug-resistant tumors.

Aged↗

PubMed1992

Uptake of 2-fluoro-2-deoxy-D-[U-14C]-glucose during chemotherapy in murine Lewis lung tumor.

Mice bearing intramuscular Lewis lung tumor were treated with BCNU and doxorubicin (ADM) to study chemotherapy-induced changes in the uptake of 2-fluoro-2-deoxy-[U-14C]glucose (FDG). A decreased FDG uptake, tumor regression and a diminished proportion of aneuploid versus diploid cells as evaluated by DNA flow cytometry were seen after treatment with BCNU but not with ADM; HPLC indicated that most of the 14C activity in tumors was from FDG6-phosphate. The results suggest that changes in FDG uptake reflect the effectiveness of antitumor therapy. FDG may be valuable in follow-up studies of cancer treatment.

Adenosine Triphosphate↗

PubMed1992

Tumour growth rate and DNA flow cytometry parameters as prognostic factors in metastatic melanoma.

The prognostic value of flow cytometric parameters and tumour growth rate of melanoma metastases under the mouse renal capsule was investigated for tumours from 117 consecutive patients referred to the Helsinki University Central Hospital Melanoma Team. DNA flow cytometry (FCM) was interpretable for the tumours of 114 patients, and growth rate analysis for 82 patients, both results being available from 79 patients. Thirty-six percent of the tumours were DNA diploid and 64% DNA aneuploid. Tumour ploidy and S-phase fraction were shown by multivariate Cox model analysis to be independent prognostic variables and major determinants of survival after first recurrence. Patients with DNA diploid or aneuploid tumours survived a median 16 and 27 months, respectively. A high growth rate of tumour sample in vivo under the mouse renal capsule tended to be a sign of poor prognosis, although not reaching statistical significance. Combining the results of FCM, tumour growth rate and TNM stage, we propose a highly efficient prognostic scoring method. Patients with a score above 0.75 had a median survival of 11 months compared to 30 months among patients scoring under 0.75 (P less than 0.0001). This score was the most significant (P less than 0.0001) prognostic factor in the Cox model when TNM stage, age, ploidy, SPF, and tumour growth rate were analysed as covariates.

Adult↗

PubMed1992

Agonistic and antagonistic effects of antiestrogens in different target organs.

Antiestrogens block by definition specifically the actions of estrogens. In the classical uterotropic assay in immature rodents, where estrogens cause fluid retention and cell proliferation, triphenylethylenes have also species-specific estrogen-like (agonistic) effects. 4-hydroxylated triphenylethylenes have in general less estrogenic properties than unhydroxylated ones, and ICI 164,384 has no estrogenic activity in this model. Uterus responds to estrogens by stimulation of cell proliferation. Some other tissues, like breast, liver, and bone respond by regulation of specific protein synthesis. Some of the proteins act as growth factors, and some have unknown functions. The regulation of gene expression is a complex phenomenon: estrogens may turn the responsive gene on or off. Similarly antiestrogens may participate in the gene regulation by mimicking or antagonising estrogen-like actions. This paper summarizes the estrogenic and antiestrogenic effects of classical and new antiestrogens in different tissues.

Animals↗